Public scientific research is one of Britain’s great unsung industries. Its turnover is around £8bn, it employs some 100,000 researchers and it leads the world. After the US, we produce more cited research papers than anyone else. We’re not as good as we should be in translating all that effort into companies, products and services. But without its stimulus, our moderate levels of private business research, itself employing another 150,000 researchers, would be even lower. Nonetheless, as a self-standing industry, public scientific research is one of our most competitive and a top exporter.

Or it was. It is one of the many areas of our economic life likely to take an irreparable hit as Britain leaves the EU. Britain’s leadership position was built on the excellence of its science, capacity to attract talent and the extraordinary ability of its scientists to build international networks bidding for EU research money. The EU is spending £70bn on scientific research in its Horizon 2020 programme: up until 23 June, more of it was being allocated to British-led partnerships than any other member state.

Three-quarters of all the increase in scientific funding to universities has come from the EU over the last few years. Just as importantly, science has long since gone international, whatever Ukip and Tory Brexiters may think; the world’s biggest research base and generator of science is the EU: 64% of British scientific research is built on international collaborations, unerpinned by EU funding, now contributing nearly one in five research pounds spent in British universities.

Researchers from Europe, joining these collaborations, could live in Britain freely. Unless Boris Johnson and lead Brexit negotiator David Davis stop babbling about possible trade deals years hence outside the EU and become unexpectedly non-ideological and nimble – and Theresa May and home secretary, Amber Rudd, very pragmatic about immigration – British science is about to be very badly hurt.

Mike Galsworthy, director of Scientists for EU, already reports 378 responses to his Brexit impact monitoring database . Over a quarter have encountered problems with being part of consortiums bidding for intensely competitive Horizon 2020 funding. Everyone fears the risks in a few years of having non-EU Britain as a partner. Worse still are reports of xenophobia cited by EU research scientists in their daily life in buses, trains, shops and from neighbours. Word is spreading fast: don’t come to Britain. From being at the heart of European scientific research, Britain is going to the margins, with incalculable consequences for our knowledge base, the standing of our universities and research jobs.

It is the same across the board. All the relatively strong parts of our otherwise weak economy have built their strength on EU membership and after more than 40 years the links are deep – and very expensive to unravel. The single market offers a “passport” to all member state companies, allowing them to do business anywhere in the EU without further certification or regulation.

This has all the ingredients of not just a Brexit recession but one followed by protracted stagnation

Banks and insurance companies have already begun quietly moving their bases to within the EU to sustain their ability to trade via the bank passport: Airbus at last week’s Farnborough airshow made the same point – it did not want to plough through thousands of pages of UK regulations to invest in Britain. Rolls-Royce similarly. Bank of England agents across the country report that the majority of investment proposals have been frozen; inward investment has trickled to nothing. The Royal Institute of Chartered Surveyors reports the sharpest fall in expectations of rising house prices since 2004.

This has all the ingredients of not just a Brexit recession but one followed by protracted stagnation. I think the risks of a credit crunch are understated, despite the Bank of England allowing banks to use more of their capital buffer to support new lending. Property prices for farmland and commercial property are dependent on either the common agricultural policy supporting farmland prices or the nearly 500 multinationals headquartered in Britain demanding office space because of our access to the single market. Prices could plunge, with huge loan write-downs inevitable.

Moreover, as the Bank of England’s chief economist, Andy Haldane, recently remarked in an important speech, the British recovery is much more anaemic than widely reported. “So far at least,” he said, “this has been a recovery for the too few rather than the too many, a recovery delivering a little too little rather than far too much.” It has been a jobs rich but pay poor recovery, with half of UK households seeing no increase in their disposable income since 2005 – a lost decade of income. It has been the young and those in the regions who have suffered worst.

Brexit will make all this much worse, but badly handled by the Brexiters catapulted into leading the negotiations, it could morph into a catastrophe. David Davis airily dismissed these risks in an article for ConservativeHome before his appointment. His favoured option was for Britain to trade with the EU under essentially World Trade Organisation rules in a dreamland where there are only benefits and no costs.

Theresa May is trying hard; including Scotland in the talks as she has promised makes Brexiter stupidity a bit less likely. All the country’s economic constituencies – manufacturing, science, the creative industries, energy, finance – need to make it plain as the recession gathers momentum how crucial it is that we stay as close to the EU as possible and demand their role in the talks too, as should parliament.

Sixteen million of us voted to remain: many who voted to leave will reconsider as the facts that were withheld by a propagandist press and callow, cowed BBC become more obvious. The country was lied to by the hard right and its allies on a scale not witnessed in our history. To argue that the resulting vote at one moment in time represents Britain’s last word on the matter is a travesty of democracy, especially as the consequences unfold.

Democracies discuss and debate, especially when they risk going over a cliff. It may take the 16 million to form a new political party to make the case as Labour dies. It’s our country too and we don’t need to live in a xenophobic economic dead zone.